1. Field of the Invention
The present invention relates to a method of manufacturing a thermal head, and a thermal printer.
2. Description of the Related Art
As a method of manufacturing a thermal head to be used in a thermal printer, there is known a method of forming an opening portion in one surface of a support substrate and bonding an upper substrate onto the support substrate in a laminated state so as to close the opening portion. In this manufacturing method, a heating resistor is formed on a surface of the upper substrate at a position opposed to the opening portion across the upper substrate, and then a protective film is formed to cover the heating resistor and the surface of the upper substrate, to thereby manufacture a thermal head having a cavity portion formed therein between the support substrate and the upper substrate.
In this case, a resistance value of the heating resistor is adjusted based on a thickness dimension of the upper substrate, and hence it is possible to easily manufacture a highly-efficient thermal head capable of accurately outputting a target heating amount that takes into account the amount of heat which is not utilized and wasted.
In the above-mentioned manufacturing method, the thickness dimension of the upper substrate is divided into sections at predetermined intervals, and a database that stores the resistance value of the heating resistor in association with each section is prepared. After the thickness dimension of the upper substrate is measured, the resistance value of the heating resistor corresponding to the measured thickness dimension is read from the database, and the resistance value of the heating resistor is adjusted.
However, the resistance value of the heating resistor varies for each substrate or each lot. Therefore, there is a disadvantage in that, in the vicinity of both ends of each section of the thickness dimension of the upper substrate, a proper resistance value cannot be obtained, resulting in lowering heating efficiency.
Therefore, in this field, a method of manufacturing a thermal head, and a thermal printer which are capable of suppressing the variation in heating efficiency caused by the variation in resistance value among substrates or lots have been sought after.